How to Win at Rock-Paper-Scissors

Ubs pointed me to this entry at Mental Floss linking to this article by Graham Walker, who’s described as “a co-author of the Official Rock Paper Scissors Strategy Guide (published by Simon and Schuster) and five-time organizer of the World Rock Paper Scissors Championships.” Hey, I wanted to organize a RPS tournament one winter in college but everybody thought it was a silly idea. Credit goes to those who put in the effort.

Anyway, here are Walker’s suggestions. I thought it was just going to be a joke–“rock always ins” and all that–but they actually look pretty good to me. The comments at the end of the article are interesting too.

The secret to winning at RPS

Basically, there are two ways to win at RPS. First is to take one throw away from your opponent options. ie – If you can get your opponent to not play rock, then you can safely go with scissors as it will win against paper and stalemate against itself. Seems impossible right? Not if you know the subtle ways you can manipulate someone. The art is to not let them know you are eliminating one of their options. The second way is to force you opponent into making a predictable move. Obviously, the key is that it has to be done without them realizing that you are manipulating them.

Most of the following techniques use variations on these basic principles. How well it works for you depends upon how well you can subtly manipulate your opponent without them figuring out what you are doing. So, now that the background is out of the way, let’s get into these techniques:

1 – Rock is for Rookies

In RPS circles a common mantra is “Rock is for Rookies” because males have a tendency to lead with Rock on their opening throw. It has a lot to do with idea that Rock is perceived as “strong” and forceful”, so guys tend to fall back on it. Use this knowledge to take an easy first win by playing Paper. This tactic is best done in pedestrian matches against someone who doesn’t play that much and generally won’t work in tournament play.

2 – Scissors on First

The second step in the ‘Rock is for Rookies’ line of thinking is to play scissors as your opening move against a more experienced player. Since you know they won’t come out with rock (since it is too obvious), scissors is your obvious safe move to win against paper or stalemate to itself.

3 – The Double Run

When playing with someone who is not experienced at the RPS, look out for double runs or in other words, the same throw twice. When this happens you can safely eliminate that throw and guarantee yourself at worst a stalemate in the next game. So, when you see a two-Scissor run, you know their next move will be Rock or Paper, so Paper is your best move. Why does this work? People hate being predictable and the perceived hallmark of predictability is to come out with the same throw three times in row.

4 – Telegraph Your Throw

Tell your opponent what you are going to throw and then actually throw what you said. Why? As long as you are not playing someone who actually thinks you are bold enough to telegraph your throw and then actually deliver it, you can eliminate the throw that beats the throw you are telegraphing. So, if you announce rock, your opponent won’t play paper which means coming out with that scissors will give you at worst a stalemate and at best the win.

5 – Step Ahead Thinking

Don’t know what to do for your next throw? Try playing the throw that would have lost to your opponents last throw? Sounds weird but it works more often than not, why? Inexperienced (or flustered) players will often subconsciously deliver the throw that beat their last one. Therefore, if your opponent played paper, they will very often play Scissors, so you go Rock. This is a good tactic in a stalemate situation or when your opponent lost their last game. It is not as successful after a player has won the last game as they are generally in a more confident state of mind which causes them to be more active in choosing their next throw.

6 – Suggest A Throw

When playing against someone who asks you to remind them about the rules, take the opportunity to subtly “suggest a throw” as you explain to them by physically showing them the throw you want them to play. ie “Paper beats Rock, Rock beats scissors (show scissors), Scissors (show scissors again) beats paper.” Believe it or not, when people are not paying attention their subconscious mind will often accept your “suggestion”. A very similar technique is used by magicians to get someone to take a specific card from the deck.

7 – When All Else Fails Go With Paper

Haven’t a clue what to throw next? Then go with Paper. Why? Statistically, in competition play, it has been observed that scissors is thrown the least often. Specifically, it gets delivered 29.6% of the time, so it slightly under-indexes against the expected average of 33.33% by 3.73%. Obviously, knowing this only gives you a slight advantage, but in a situation where you just don’t know what to do, even a slight edge is better than none at all.

8 – The Rounder’s Ploy

This technique falls into more of a ‘cheating’ category, but if you have no honour and can live with yourself the next day, you can use it to get an edge. The way it works is when you suggest a game with someone, make no mention of the number of rounds you are going to play. Play the first match and if you win, take it is as a win. If you lose, without missing a beat start playing the ‘next’ round on the assumption that it was a best 2 out of 3. No doubt you will hear protests from your opponent but stay firm and remind them that ‘no one plays best of one for a kind of decision that you two are making’. No this devious technique won’t guarantee you the win, but it will give you a chance to battle back to even and start again.

Walker (not “Thrower,” huh?) introduces these suggestions with an excellent perspective on game theory:

Contrary to what you might think RPS is not simply a game of luck or chance. While it is true that from a mathematical perspective the ‘optimum’ strategy is to play randomly, it still is not a winning strategy for two reasons. First, ‘optimum’ in this case means you should win, lose and draw an equal number of times (hardly a winning strategy over the long term). Second, Humans, try as they might, are terrible at trying to be random, in fact often humans in trying to approximate randomness become quite predictable. So knowing that there is always something motivating your opponent’s actions, there are a couple of tricks and techniques that you can use to tip the balance in your favour.

Something about that British spelling makes it all seem so much more sophisticated. . . . One other thing: the Mental Floss entry has some commenters who mention the Dynamite throw. I remember playing best-of-5 as a kid with Dynamite (fist clenched with index finger out) as an option. Dynamite beat all the other options (except it tied with Dynamite, of course) but you could only throw it once during the best-of-5 game.

Finally, as I’m sure many people have pointed out, some aspects of RPS are mirrored in the interaction between baseball pitcher and hitter, since the batter has to pretty much guess at the pitch before it’s thrown (with some room for adjustment).

6 Comments

There have been some attempts to get computers to play rock-paper-scissors against each other, e.g. the RoShamBo Programming Competition. Tough because most of these psychological tricks won't work. Of course, you can use the obvious mixed strategy, but nobody would win the contest if everyone did that. (Well, not decisively anyway.) So they try to be smart in simultaneously having a hard to predict pattern and predicting the patterns of others.

There was a computer (an Ohio Scientific) in our high school, and one day I wrote a program to play rock, paper, scissors. It had a simple algorithm based on a mix of randomness and the opponent's earlier plays. Some of my friends came by to play it and, without even knowing the algorithm, beat it.

There's strategy, and there's strategy. For more than 18 months I told all my opponents that I was going to play scissors twice in every RPS game I played. And I always did.

Except for the last time.

By then, all the 20+ other people in the room had played me at one time or another, and I think they heard something in my voice when I asked if my challenger "just wanted to play RPS for it." Before we started, they all gathered around us in a circle with knowing smiles, and they told my opponent that I never ever didn't play Scissors twice when I said I would.

And then, because they saw the amused and knowing look on my face, they started to question it aloud (because of what was at stake this time)… and completely flummoxed my opponent.

Turns out I did play it, that last time, but by the time the crowd had talked him out of it he absolutely didn't expect me to.